Vertebral osteomyelitis refers to inflammation and/or infection of the vertebral body, while diskospondylitis involves the associated discs. In order to get a better picture of this rare but challenging disease, Coleman and her group conducted a retrospective study of foals affected with VOD. She described their results at the 2012 Convention of the American Association of Equine Practitioners, held Dec. 1-5 in Anaheim, Calif.

Clinical signs of VOD in horses most commonly include fever, lethargy, increased heart rate, increased respiration rate, and loss of appetite. Affected horses might also exhibit stiffness, pain on palpation, swelling over the vertebrae (most noticeable in the neck), lameness, and swollen lymph nodes. Because these signs are nonspecific, it can be difficult to make a clinical diagnosis.

Coleman listed several theoretical causes of VOD, such as spread of bacteria through the bloodstream; commonly, veterinarians see this following systemic infections in dogs and they speculate that a similar process could happen in foals with sepsis due to failure of passive transfer of maternal antibodies. However, scientists have not completed research to support this hypothesis. Localized invasion or infection from something like an injection or puncture wound could also cause VOD, as could crushing trauma (ie. from flipping over).

In order to gain a better clinical picture of equine VOD, the research team analyzed the records of 17 foals that were less than 1 year old with a clinical diagnosis of VOD and displayed more than one sign of bone or disc degeneration on necropsy or imaging data. For foals diagnosed via necropsy, pathologists had to confirm diagnosis with histopathology or by the presence of more than two points of gross evidence of VOD. Investigators excluded animals with fistulous withers from the study.

They included 11 colts and six fillies aged 2 weeks to 4 months old in the study. The foals' clinical signs were consistent with those described. Nine of the 17 foals did not survive to hospital discharge. Investigators discovered that radiographic signs lagged behind clinical disease.

VOD is an uncommon but serious condition in the horse. Although early diagnosis is critical to treatment, diagnosis could be confounded by the highly variable and nonspecific signs of the disease. Coleman said that, ideally, subsequent epidemiologic studies could help veterinarians determine risk factors for development.

About the Author

Christy Corp-Minamiji, DVM, practices large animal medicine in Northern California, with particular interests in equine wound management and geriatric equine care. She and her husband have three children, and she writes fiction and creative nonfiction in her spare time.

Stay on top of the most recent Horse Health news with FREE weekly newsletters from TheHorse.com. Learn More

Featured Adoptable Horse

Pride

He is a sweet 22 year old, lots of spunk and life left. Has been used in arena and trail. Very acceptive. Just need to find him a GREAT LOVING home. Has been off for a cousin le years but I don't think he'd be hard at all to get back in gear. Read More